Dial up-new home number

A simple problem but for the life of me I can't remember how to do it!

A pal in Scotland rung me. He's running ME with a Virgin dial up account. He's moved his PC from his house to his business. Same area code but different number. How does he change his settings to reconnect to the net please?

Oh right I was under the impression you had to put in the number that you were dialling from!Must be something else then as he can't connect at the moment and he doesn't have to put a 9 in to get an outside line.